The utility model relates to a pressurizing device for multistage outer circular shielding pumps, which comprises a multistage pump, an outer circular shielding motor and an exhaust valve, wherein a pressurizing device is arranged between the multistage pump and the outer circular shielding motor. The surface of a cylinder of the pressurizing device is provided with a thread groove with annular gaps. The outer circular shielding motor is provided with an outer circular pipe passage. One end of the outer circular pipe passage is arranged on the top end of the outer circular shielding motor, and the other end is communicated with a spitting section. The surface of the utility model is thread grooves. The mechanical energy of the outer circular shielding motor is transmitted to a vertical or horizontal pressurizing device for multistage outer circular shielding pumps through a main shaft which rotates at a high speed, the energy (comprises speed energy, pressure energy and position energy) of liquid is increased through the pressurizing device applying work for the conveyed liquid, the pressurizing device rotates at a high speed, and the liquid is forced to be conveyed to a pump cavity from a motor cavity for reaching the purpose of non-contact pressurizing for pumps. The utility model conveys liquid to the pump cavity from the motor cavity for generating pump conveying flow. Pressure generated by the utility model can increase the pressure of liquid flow in the motor cavity for accelerating liquid in the motor cavity flow into the pump cavity.